You intercept another message TCTES WSGHU ORAAR HESMI LYIT (Note: it is usual to insert a space after every fifth letter, but these spaces should be ignored when finding the size/shape of the grid.) a) b) c) Count the letters. What possibilities are there for the shape of the grid? Find the correct shape for the grid and then unscramble the message. Suppose you wanted to scramble the message A BAYONET IS A WEAPON WITH A WORKER AT EACH END This has 37 letters. The only grids with 37 spaces would have either one row or one column and would not scramble the message. Why not? 37 is an example of a prime number, a number that is not divisible by any number other than itself or one. To make it fit a more convenient grid we can add extra letters at the end that do not form part of the message, but just fill the space. It is common to use 'unusual' letters, for example, X. Such letters are commonly known as dummy letters.